It might appear that having highly expressive notations is an advantage in writing specifications and subsequently reasoning about programs. Even for sequential programs, this is not always true: simple type systems that are statically decidable or fixed formats of specifications that yield intuitive proof obligations both indicate that constrained expressiveness can increase tractability. The aim...
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Summary form only given. Hybrid systems are composed by continuous physical component and discrete control component where the system state evolves over time according to interacting law of discrete and continuous dynamics. Combinations of computation and control can lead to very complicated system designs We treat more explicit hybrid models by providing a hybrid relation calculus, where both clo...
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Summary form only given. Software evolution is an essential activity that adapts existing software to changes in requirements. It has played a central role in the overall software lifecycle in recent years. It is generally acknowledged that the software employed in real-world environments must continuously evolve and adapt. Many studies, on the other hand, have suggested that software evolution co...
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Large-scale systems are often modeled and verified in a component-based way. BIP (Behavior, Interaction, Priority) is a flexible component-based framework which supports hierarchical design of heterogeneous systems. BIP components interact via connectors in which data can be passed among multiple components. It also support the modeling of time. Due to its expressiveness and flexibility, many real...
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SPACE is a model-driven engineering technique for reactive distributed systems. It enables to develop system models from reusable building blocks, formal analysis by model checking as well as automated transformation to executable code. In this paper, we describe an extension of the SPACE formalism which allows to model and verify also real-time behavior. In particular, one specifies real-time con...
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In the Semantic (Web) Services area, services are considered black boxes with a semantic description of their interfaces as to allow for precise service selection and configuration. The semantic description is usually grounded on domain-specific concepts as modeled in ontologies. This accounts to types used in service signatures, but also to predicates occurring in preconditions and effects of ser...
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CosyVerif aims at gathering within a common framework various existing tools for specification and verification. It has been designed in order to 1) support different formalisms with the ability to easily create new ones, 2) provide a graphical user interface for every formalism, 3) include verification tools called via the graphical interface or via an API as a Web service, and 4) offer the possi...
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It is a great challenge to evaluate self-adaptive software rigorously. This paper first discusses the key aspects of adaptation of software and points out that the adaptation level of a software system is determined by how well the system satisfies the user's expectations through adjusting its behavior or configuration to tackle the changes in the environment. Accordingly, the paper puts forward a...
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In this paper, we focus on networked, embedded systems which may contain numerous electronic control units, connected by multiple network busses. Furthermore, such embedded systems support many runtime configurations. The main problem is to determine the network resource needs of all variations permitted at runtime, i.e. to calculate the worst case resource needs. We describe the runtime variabili...
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To reduce the cost and risk of the development of system of systems (SoS) by pre-evaluation before the SoS is built, a model-driven approach is proposed to evaluate the SoS based on its architecture, especially focused on measures of performance and effectiveness. In order to implement the pre-evaluation, the system architecture needs to be transformed to the simulation model of the system under t...
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We coalgebraically define a unified semantics for systems with an emphasis on the notion of time. Such a semantics intends to formalize system that underly system engineering (i.e. the discipline focusing on the integration mastery of large industrial systems).Moreover, we give a formal meaning to another important aspect of systems engineering: system requirements, constraining the expected prope...
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The use of formal methods for developing software is increasing. However in many cases only a model of the system is validated against a set of specifications. The actual implementation may thus not correspond to the formal model. One approach to this problem is to directly verify the actual implementation. Another solution is to provide a refinement scheme for the model. In this paper we present ...
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Temporal induction is a SAT-based model checking technique. We prove that the SAT instances generated by its induction rule can be reduced to the so called Incremental CNFs. A new DPLL procedure is customized for Incremental CNFs, so that the intermediate results in solving previous instances, including the learnt clauses and the search tree, can be reused in solving the next instance. To the best...
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Wireless systems have a wide range of applications recently. To explore complex features of such systems, formalisms are proposed to specify and reason about them. This paper presents a case study of routing protocol in wireless networks. We formalize the route discovery process of AODV routing protocol using Object-Z. Network topology and local variables of nodes are defined by relations and func...
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Cyber-Physical Systems (CPSs) integrate computing, communication and control processes. Close interactions between the cyber and physical worlds occur in time and space frequently. Therefore, both temporal and spatial information should be taken into consideration when specifying properties of CPS systems for verification. However, how to formulate properties specifying spatial together with tempo...
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Asynchronous multi-agent systems (AMAS) are multi-agent systems with asynchronous updates and communications. They are often designed from the point of view of local computations and the interactions of autonomous agents. However, often some functionality of the system is proposed from the global point of view. It is not always possible to verify such global functionality under total, random, asyn...
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TiMo is a process calculus for mobile systems where timers could be to used to control process mobility and interaction. Despite its syntactic simplicity, TiMo is able to describe complex systems. Interesting properties of such systems refers to process migration, time constraints, bounded liveness and optimal reachability. In this work we describe a tool, called TiMo@PAT, developed by using Proce...
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